The Epistles of John, assigned to the writer of the Fourth Gospel and the Revelation, testify that God is love and that love is the test of religion. Second John is written to “the elect lady and her children,” probably a church; Third John is addressed to “the beloved Gaius.”

1 John 2

2:5 But whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him.